Catalan authorities will not follow orders from the Spanish government if Madrid moves to reassert control over the region, a senior official says.
Foreign affairs spokesman Raul Romeva told the BBC the central government was acting against the will of Catalans.
Spain’s Prime Minister Mariano Rajoy has announced plans to sack the region’s government and curtail some of the freedoms of its parliament.
Separatist parties in Catalonia are due to discuss their plans later.
The Spanish Senate is expected to approve the government’s measures on Friday along with a proposal for fresh regional elections.
How did we get here?
A referendum outlawed by Spain was held on 1 October in Catalonia.
The Catalan government, led by President Carles Puigdemont, said that of the 43% said to have taken part, 90% were in favour of independence.
Unionist parties who won about 40% of the vote at the 2015 Catalan elections boycotted the ballot and many anti-independence supporters stayed away, arguing it was not valid.
Mr Romeva said the people of Catalonia had voted for independence and the Spanish government needed to recognise that.
Commenting on the possibility of direct rule by Madrid, he added: “How can the European Union live with that situation [if this happens]. How can the EU democracy survive and how can they be credible if they allow this to happen?
“Because what I can tell you is that the people and the institutions in Catalonia will not let this to happen.”
What happens next?
Mr Puigdemont has said his government will not accept direct rule.
Apart from stripping Carles Puigdemont of all his powers, the central government will also seek to take control of Catalonia’s local police force and its public broadcaster, TV3, reports suggest.
Appeals by separatists for outside intervention in the crisis have had little effect, with the EU taking the position it is an internal affair for Spain to decide.